Chiropractic Vertebral Subluxations: Science vs. Pseudoscience

A 1997 publication by the Foundation for Chiropractic Education and Research, supporting the vertebral subluxation theory, noted that “…we [chiropractors] have successfully distanced the concept of a chiropractic subluxation from that of an orthopedic subluxation.”1 When discussing “subluxations” or misaligned vertebrae, however, chiropractors often fail to point out the difference between an orthopedic subluxation and a chiropractic subluxation. Reference to subluxations in medical literature is often presented as support for the practice of chiropractic as a method of adjusting vertebral subluxations to “restore and maintain health.”

In the eyes of the public, the chiropractic vertebral subluxation theory has confused the definition of the word “subluxation,” a common medical term. Unlike the mysterious, undetectable and asymptomatic chiropractic “vertebral subluxation complex” alleged to be a cause of disease, a real vertebral subluxation, that is, an orthopedic subluxation, can be a cause of mechanical and neuromusculoskeletal symptoms but has never been associated with organic disease.

Subluxations: Real and imaginary

An orthopedic subluxation, recognized and named as such since the days of Hippocrates, is a painful partial dislocation. Simple misalignment of a vertebra, also referred to as a “subluxation,” is commonly caused by disc degeneration, curvatures, spondylolysis, and structural abnormalities. Such a subluxation may or may not be mechanically symptomatic and can be seen on a plain x-ray image. In the absence of pathology such as disc herniation or osteophyte formation, these common vertebral subluxations or misalignments rarely affect spinal nerves and have never been associated with organic disease. Spinal nerves supply musculoskeletal structures. The body’s organs are supplied primarily by autonomic nerve ganglia and plexuses located outside the spinal column and by cranial and sacral nerves that pass through solid bony openings, providing overlapping nerve supply independent of any one spinal nerve that passes between two vertebrae.

An orthopedic subluxation, a true vertebral misalignment, or a mechanical joint dysfunction that affects mobility in the spine is not the same as a “chiropractic subluxation” that is alleged to cause disease by interfering with nerve supply to organs. Such a subluxation has never been proven to exist. There is no plausible theory and no credible evidence to support the contention that “nerve interference” originating in a single spinal segment can cause an organic disease.
Unable to provide evidence that commonly occurring vertebral misalignment can cause organic disease, advocates of the subluxation theory have reasoned that there must be some other type of joint dysfunction that can affect general health. They have chosen, by consensus, to call this undetectable lesion a “vertebral subluxation complex,” which “embraces the holistic nature of the human body, including health, well-being, and the doctor/patient relationship as well as the changes in nerve, muscle, connective, and vascular tissues which are understood to accompany the kinesiologic aberrations of spinal articulations.”1

Some chiropractors claim to be able to locate these elusive subluxations by using surface electromyography, thermography, vibratory instruments, leg length checks, or by palpating the spine.

A largely ignored landmark review of the literature by a Ph.D. and a chiropractor (Nansel and Szlazak), published in 1995, concluded that there is not a single appropriately controlled study to indicate that any dysfunction in structures of the spinal column is a cause of organic disease.2 The review noted that pain and other symptoms referred from a spinal segment can “create overt signs and symptoms that can mimic, or simulate (rather than cause), internal organ disease,” lending no support to the vertebral subluxation theory. Spinal nerves are commonly irritated or compressed, causing pain and other symptoms in the musculoskeletal structures supplied by the affected nerve. But even the most severe compression of a spinal nerve does not cause organic disease.

A review of the current evidence on the epidemiology of the subluxation construct (Mirtz, et al, 2009) also failed to find any credible evidence supporting the chiropractic vertebral subluxation theory. This paper, authored by three chiropractors and a Ph.D., concluded that “No supportive evidence is found for the chiropractic subluxation being associated with any disease process or of creating suboptimal health conditions requiring intervention. Regardless of popular appeal this leaves the subluxation construct in the realm of unsupported speculation. This lack of supportive evidence suggests the subluxation construct has no valid clinical applicability.”3

While there is justification for use of the word “subluxation” when referring to a mechanical-type spinal problem, there appears to be no justification whatsoever for suggesting that a “chiropractic subluxation” can affect general health.

A chiropractic subluxation by any other name…

If the chiropractic profession dumped the subluxation theory and took the steps needed to become a physical-treatment specialty in the care of mechanical-type neck and back problems, it could remain open to future research that might reveal evidence that spinal manipulation benefits general health─a finding that would be a bonus for use of manual therapy. Until then, the theory that adjusting a “vertebral subluxation complex” will restore and maintain health is too implausible to warrant support by the scientific community.

Unfortunately, the chiropractic profession in the United States continues to be defined by subluxation theory. Too few chiropractors are willing to “step out of line” and announce that the theory (more accurately defined as a belief) is scientifically indefensible and should be dumped. Failure of chiropractic associations to publicly disagree with subluxationists who identify chiropractic as a method of adjusting the vertebral subluxation complex keeps chiropractic marginalized and subject to ridicule by the scientific community. Without some identifying label or degree that distinguishes science-based chiropractors from subluxation-based chiropractors, medical physicians will continue to be reluctant to refer a patient to a chiropractor, lest they deliver a patient into the hands of a pseudoscientific practitioner whose philosophy embraces an anti-medical approach and endangers the patient. Science-based chiropractors who are properly specialized should openly announce their limitations if they are to earn the recognition and trust of medical professionals who can provide the referrals needed to sustain a specialized practice.

In May of 2010, the British General Chiropractic Council (GCC) advised members of the British Chiropractic Association (BCA) that “The chiropractic Vertebral Subluxation Complex…is not supported by any clinical research evidence that would allow claims to be made that it is the cause of disease or health concerns.”4 Chiropractors were advised to provide evidence-based care that “incorporates the best available evidence from research, the preferences of the patient and the expertise of practitioners including the individual chiropractor her/himself.”4 In response, the British Chiropractic Association advised its members to “refrain from making any reference to Vertebral Subluxation Complex in media to which their patients or the general public may have access,” adding that “this advice has no bearing on scope of practice.”4

While the action of the GCC and the BCA in avoiding reference to the Vertebral Subluxation Complex is an important and unprecedented move in the right direction, it appears that the door was left open for British chiropractors to continue treating a broad scope of health problems. Such leniency would not restrict use of a variety of unproven treatment methods (originally based on the vertebral subluxation theory) promoted by individual chiropractors and preferred by indoctrinated patients.

Although many chiropractors are now backing away from the chiropractic vertebral subluxation theory, many continue to use the theory to justify treating a broad scope of health problems by “adjusting” the spine. They simply point to legal and dictionary definitions of chiropractic to support their claims. Some who do not use the word “subluxation” simply substitute another word or words, such as “joint dysfunction,” in support of their belief that some kind of segmental spinal “lesion” can affect overall health.

Spinal manipulation stigmatized by subluxation theory

The basic definition of chiropractic provides opportunity for pseudoscientific spinal manipulators who treat a broad scope of health problems with a myriad of implausible and unproven treatment methods, alienating an informed public along with the scientific community.

According to a study published in 2005, the percentage of the US population seeing chiropractors annually for various reasons decreased from 9.9% in 1997 to 7.4% in 2002.5 Using data from a 2002 National Health Interview Survey, a study published in a 2010 issue of The Journal of the American Board of Family Medicine reported that about 6% of the US population used complementary alternative medicine (CAM) to treat their back pain. About 74% of this 6% (about 4.4% of the population) went to chiropractors; 22% went to massage therapists.6 Since conventional medical practitioners traditionally refer back-pain patients to physical therapists, physiatrists, or orthopedic surgeons, physician referral to CAM practitioners remains low.

The chiropractic profession would be well advised to make the changes needed for recognition as specialists in the care of mechanical-type back pain, “the second leading reason for ambulatory office visits” and the most common reason for use of CAM in the United States.6

Science-based chiropractors who do not subscribe to the chiropractic vertebral subluxation theory, who specialize in the use of manipulation and other physical treatment methods in the care of mechanical-type neck and back problems, will use manipulation more appropriately. Unfortunately, there is no recognized label, degree, or association that distinguishes such chiropractors from subluxation-based chiropractors. Without a clear choice in selecting a good chiropractor, few physicians will risk referring their patients to a chiropractor, making survival difficult for properly specialized chiropractors.

As Sir James Frazer wrote in 1922, “The ablest man is dragged down by the weakest and dullest, who necessarily sets the standard, since he cannot rise, while the other can fall.”7

Belief system perpetuates status quo

Since my graduation from a chiropractic college in 1956, arguments and opinions about chiropractic have changed very little. No one seems to know what chiropractic is or what it does. No two chiropractors can agree on how to treat a specific ailment or which vertebrae to adjust. There are at least 97 named antithetical adjustive techniques,8 all based on a nonsensical, nonfalsifiable chiropractic vertebral subluxation theory. The chiropractic profession as a whole has yet to be properly defined and specialized so that diagnosis and treatment methods are uniformly consistent and interchangeable among chiropractors. Subluxation-based chiropractic continues to be at odds with mainstream health care.

Although the public generally thinks of a chiropractor as a “back doctor,” societal suspicion keeps utilization of chiropractic low. In a cycle perpetuated by the definition of chiropractic, science takes a back seat to standards that allow some chiropractors to follow a 19th century philosophy formulated by a magnetic healer 115 years ago. So far, the chiropractic profession has failed to take a stand and draw a line that separates sense from nonsense in chiropractic care, keeping the profession on the fringe of health care and in the realm of alternative medicine. The Chiropractic Paradigm formulated by the Association of Chiropractic Colleges (ACC), representing North American Chiropractic Colleges, proposes that “Chiropractic is concerned with the preservation and restoration of health and focuses particular attention on the subluxation.”9,10 The purpose of chiropractic is to “optimize health.” This vague and untestable ACC paradigm has been endorsed by the American Chiropractic Association, the International Chiropractic Association, and the World Federation of Chiropractic. The ACC notes that “Because of the emphasis on holistic health care, chiropractic is associated with the field of complementary and alternative medicine.”11

Until chiropractic schools and associations draw a line (with the fanfare of a clarion call) and take a stand on the side of science as a properly limited specialty, uniformly defining and limiting chiropractic in state laws, the credibility and the status of chiropractors will remain low. Physicians will continue to refer their patients to physical therapists, physiatrists, and orthopedic surgeons rather than risk a bad outcome with inappropriate treatment provided by a chiropractor. With an increasing number of physical therapists and orthopedic manual therapists now including spinal manipulation in their treatment armamentarium, it may eventually become unnecessary to search for the manipulative services of individual science-based chiropractors who are “not like the other chiropractors.”

It seems likely that subluxation-based chiropractic, like homeopathy and other belief systems, will be perpetuated to some degree by true believers. It remains to be seen whether chiropractic will eventually split into two camps─one for science-based chiropractors and one for subluxation-based chiropractors. Hopefully, the science-based camp will eventually prevail as a majority in defining chiropractic in state laws, forcing subluxation-based chiropractors to practice surreptitiously. This may never happen. But in the archives of science, the “chiropractic subluxation” will be filed away under the label of dogma.

Nonfalsifiable subluxation theory still alive

Despite the general consensus of scientific and academic groups that the chiropractic vertebral subluxation theory is not a viable construct, the National Board of Chiropractic Examiners continues to define chiropractic as subluxation-based: “The specific focus of chiropractic practice is known as the chiropractic subluxation or joint dysfunction. A subluxation is a health concern that manifests in the skeletal joints, and, through complex anatomical and physiological relationships, affects the nervous system and may lead to reduced function, disability, or illness.”9

Such a definition continues to allow routine manipulation of vertebrae anywhere in the spine to “restore and maintain health” by correcting “subluxations” or “joint dysfunction.” This approach allows frequent manipulation of the cervical spine, a treatment that has been associated with stroke caused by dissection of vertebrobasilar arteries. It’s important to remember that the chances of injury are multiplied when chiropractic neck manipulation is routinely used many times on every patient in a misguided attempt to improve health, as opposed to occasional use of neck manipulation by physical therapists and other manual therapists who are concerned only about restoring mobility in a stiff spine.

In June of 2010, the Connecticut Chiropractic Board, denying that neck manipulation can be a cause of stroke, issued this statement: “After a careful and thorough review of all the testimony and documentary evidence admitted at the hearing [January 2010], the Board concludes that there is sufficient evidence to establish that a stroke or a cervical arterial dissection is not a risk or side effect of joint mobilization, manipulation or adjustment of the cervical spine.”12 It seems unlikely that any group or organization outside of chiropractic will agree with this observation.

Because of apparent concerns that chiropractic neck manipulation based on subluxation theory involves more risk than benefit, the Kaiser Permanente Mid Atlantic States and Mid-Atlantic Permanente Medical Group recently revised their Chiropractic Manipulation Medical Coverage Policy to exclude cervical Chiropractic Manipulative Treatment (CMT). The revised policy states: “Given the paucity of data related to beneficial effects of chiropractic manipulation of the cervical spine and the real potential for catastrophic adverse effects, it was decided to exclude chiropractic manipulation of the cervical spine from coverage.”13 In response, the American Chiropractic Association “…sent a letter to Kaiser outlining the extensive data that supports cervical spine manipulation as both beneficial and safe.”14

Until the schools and associations of the chiropractic profession totally abandon the vertebral subluxation theory, and state and federal laws defining chiropractic are changed, it is not difficult to understand why there might be some justification for blanket condemnation of chiropractic, despite evidence that spinal manipulation can be useful in the treatment of uncomplicated mechanical-type back problems. It does not appear, however, that the chiropractic profession might be willing to voluntarily reduce its scope of practice by renouncing the vertebral subluxation theory. At the present time, “…the 50 state chiropractic practice acts essentially define chiropractic as the detection and correction of subluxations and assume their significance to human health, allowing a broad scope of practice. Because the chiropractic profession seems unwilling to abandon these discredited concepts, reform of the state chiropractic practice acts to eliminate subluxation-based chiropractic practice may be the only viable solution to the perpetration of unscientific and unproved healthcare practices.”15

The subluxation is the yoke of the chiropractic profession. The “chiropractic subluxation,” under one name or another, continues to find shelter under the umbrella of chiropractic. Good science-based chiropractors who do not subscribe to the vertebral subluxation theory and who use manipulation appropriately can offer a service of value. Unfortunately, such chiropractors are not easy to find.

References

Rosner A. The Role of Subluxation in Chiropractic. Des Moines, IA: Foundation for Chiropractic Education and Research; 1997.

Kanodia AK, Legedza AT, Davis RB, Eisenberg DM, Phillips RS. Perceived benefit of complementary and alternative medicine (CAM) for back pain: a national survey. The Journal of the American Board of Family Medicine. 2010;23(3):354-362.

Posted by Sam Homola

Samuel Homola is a retired chiropractor who lives in Panama City, Florida. He is the co-host of the Chirobase web site and a blogger for Science-Based Medicine. His 15 published books include Inside Chiropractic (Prometheus Books, 1999) and The Chiropractor’s Self-Help Back and Body Book, (Hunter House, 2002). His email address is samhomola at comcast.net.